Inferno tactics.

I can't stay silent, I just can't. Regarding Ifrits – it's just a simple variation of playing as Inferno; it wasn't about any specific map... if it were, it would be just a suggestion. But regarding the tactic that ONLY Inferno can use – demons. Should I explain what I mean?

They much more often give fire magic – summoning fire elementals, sacrifice...
I can't confidently say about the 4th level; there are many more magic options available in the editor...

Demonology is, again, a debatable thing. If you calculate the cost of 9 imps, it will be 450, while one demon costs 200 (I'm writing from memory, there might be some inaccuracies, don't judge me too harshly). The Castle is already expensive, and here you also have to buy imps and turn them into demons. I see the point if you have Marius.

I like playing Heroes 3.5; they often give portals, but I haven't checked in the editor. In general, maybe, maybe not.